A Point and Figure (P&F) chart is a price-action focused visualization that uses columns of X's (rising prices) and O's (falling prices) to display significant price movements while filtering out time and minor fluctuations. Unlike traditional time-based charts, P&F charts only plot a new symbol when price moves by a defined box size, and only start a new column when price reverses by a specified number of boxes (typically 3). This makes it ideal for identifying clear trends, support/resistance levels, and generating trading signals.
""" anyplot.ai
point-and-figure-basic: Point and Figure Chart
Library: pygal 3.1.0 | Python 3.13.13
Quality: 86/100 | Updated: 2026-05-20
"""
import os as _os
import sys as _sys
# This file is named pygal.py — remove its directory from sys.path first so
# Python resolves `pygal` to the installed package, not this file itself.
_here = _os.path.abspath(_os.path.dirname(__file__))
_sys.path = [p for p in _sys.path if _os.path.abspath(p or ".") != _here]
import os
import xml.etree.ElementTree as ET
import cairosvg
import numpy as np
import pygal
from pygal.style import Style
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
IMPRINT = ("#009E73", "#C475FD", "#4467A3", "#BD8233", "#AE3030", "#2ABCCD", "#954477")
# Data
np.random.seed(42)
n_days = 150
base_price = 100.0
returns = np.random.normal(0.001, 0.02, n_days)
prices = base_price * np.cumprod(1 + returns)
# P&F parameters
box_size = 2.0
reversal = 3
# P&F algorithm
columns = []
current_direction = None
current_column_start = np.floor(prices[0] / box_size) * box_size
current_column_end = current_column_start
for price in prices[1:]:
rounded_price = np.floor(price / box_size) * box_size
if current_direction is None:
if rounded_price >= current_column_end + box_size:
current_direction = "X"
current_column_end = rounded_price
elif rounded_price <= current_column_end - box_size:
current_direction = "O"
current_column_end = rounded_price
elif current_direction == "X":
if rounded_price >= current_column_end + box_size:
current_column_end = rounded_price
elif rounded_price <= current_column_end - (reversal * box_size):
columns.append((current_column_start, current_column_end, "X"))
current_column_start = current_column_end - box_size
current_column_end = rounded_price
current_direction = "O"
else:
if rounded_price <= current_column_end - box_size:
current_column_end = rounded_price
elif rounded_price >= current_column_end + (reversal * box_size):
columns.append((current_column_start, current_column_end, "O"))
current_column_start = current_column_end + box_size
current_column_end = rounded_price
current_direction = "X"
if current_direction:
columns.append((current_column_start, current_column_end, current_direction))
# Price range for y-axis
all_prices = [p for start, end, _ in columns for p in (start, end)]
y_min = min(all_prices) - box_size
y_max = max(all_prices) + box_size
y_labels = list(np.arange(y_min, y_max + box_size, box_size))
# Style
custom_style = Style(
background=PAGE_BG,
plot_background=PAGE_BG,
foreground=INK,
foreground_strong=INK,
foreground_subtle=INK_MUTED,
colors=IMPRINT,
title_font_size=66,
label_font_size=56,
major_label_font_size=44,
legend_font_size=44,
value_font_size=36,
stroke_width=3,
)
# Plot — no chart-level stroke setting so per-series stroke works correctly
chart = pygal.XY(
width=3200,
height=1800,
style=custom_style,
title="point-and-figure-basic · python · pygal · anyplot.ai",
show_legend=True,
legend_at_bottom=True,
legend_at_bottom_columns=4,
show_y_guides=True,
show_x_guides=False,
x_title="Column (Reversal)",
y_title="Price ($)",
margin=80,
margin_bottom=200,
margin_left=220,
margin_top=120,
margin_right=100,
y_labels=y_labels,
range=(y_min, y_max),
dots_size=18,
)
# Build X and O data points
x_points = []
o_points = []
for col_idx, (start, end, direction) in enumerate(columns):
low = min(start, end)
high = max(start, end)
price_levels = np.arange(low, high + box_size * 0.5, box_size)
if direction == "X":
x_points.extend((col_idx, lv) for lv in price_levels)
else:
o_points.extend((col_idx, lv) for lv in price_levels)
# Per-series stroke=False keeps dots unconnected; overrides chart default
chart.add("X (Rising)", x_points, stroke=False)
chart.add("O (Falling)", o_points, stroke=False)
# Trend lines — per-series stroke=True draws the line
support_lows = [(ci, min(s, e)) for ci, (s, e, d) in enumerate(columns) if d == "O"]
resistance_highs = [(ci, max(s, e)) for ci, (s, e, d) in enumerate(columns) if d == "X"]
if len(support_lows) >= 2:
c0, p0 = support_lows[0]
c1 = min(c0 + 6, len(columns) - 1)
chart.add(
"Support (45°)",
[(c0, p0), (c1, p0 + (c1 - c0) * box_size)],
stroke=True,
dots_size=4,
stroke_style={"width": 4, "dasharray": "8, 6"},
)
if len(resistance_highs) >= 2:
c0, p0 = resistance_highs[0]
c1 = min(c0 + 6, len(columns) - 1)
chart.add(
"Resistance (45°)",
[(c0, p0), (c1, p0 - (c1 - c0) * box_size)],
stroke=True,
dots_size=4,
stroke_style={"width": 4, "dasharray": "8, 6"},
)
def add_pnf_text_markers(svg_bytes):
"""Post-process pygal SVG: hide circle markers for X/O series, add text characters."""
SVG_NS = "http://www.w3.org/2000/svg"
ET.register_namespace("", SVG_NS)
ET.register_namespace("xlink", "http://www.w3.org/1999/xlink")
root = ET.fromstring(svg_bytes)
parent_map = {child: parent for parent in root.iter() for child in parent}
# serie-0 = X (Rising), serie-1 = O (Falling)
series_symbols = {0: ("X", IMPRINT[0]), 1: ("O", IMPRINT[1])}
for serie_idx, (symbol, color) in series_symbols.items():
for g in root.iter(f"{{{SVG_NS}}}g"):
parts = g.get("class", "").split()
if "series" not in parts or f"serie-{serie_idx}" not in parts:
continue
for circle in g.iter(f"{{{SVG_NS}}}circle"):
cx = circle.get("cx")
cy = circle.get("cy")
if cx is None or cy is None:
continue
# Hide circle; leave in DOM so hover tooltips still work in HTML
circle.set("opacity", "0")
# Add literal X or O text at the same position
text = ET.Element(f"{{{SVG_NS}}}text")
text.set("x", cx)
text.set("y", cy)
text.set("text-anchor", "middle")
text.set("dominant-baseline", "central")
text.set("font-size", "36")
text.set("font-weight", "bold")
text.set("fill", color)
text.set("font-family", "monospace, sans-serif")
text.text = symbol
parent_map[circle].append(text)
return ET.tostring(root, encoding="unicode").encode("utf-8")
# Render SVG, post-process to replace circle markers with X/O text, then save
svg_original = chart.render()
svg_modified = add_pnf_text_markers(svg_original)
# PNG — from modified SVG with X/O text characters
with open(f"plot-{THEME}.png", "wb") as f:
cairosvg.svg2png(bytestring=svg_modified, write_to=f)
# HTML — modified SVG (X/O text visible; hidden circles retain hover interaction)
with open(f"plot-{THEME}.html", "wb") as f:
f.write(svg_modified)
Part of Point and Figure Chart on anyplot.ai.